Can making machine



y 1943- .1. M. HOTHERSALL I 2,323,329

CAN -MAKING MACHINE Filed March 30, 1940 8 Sheets-Sheet 1 y 1943- J. M. HOTHERSALL 2,323,329

CAN MAKING MACHINE Filed March 30, 1940 8 Sheets-Sheet 2 YENTO y 1943- J. M. HOTHERSALL 3 2,323,329

CAN MAKING MACHINE Filed March 30, 1940 8 Sheets-Sheet 4 VENTOR 0 m & m KN SN 3N we Ni SN 5 5 y 1943- J. M. HOTHERSALL 2,323,329

CAN MAKING MACHINE Filed March 30, 1940 8 Sheets-Sheet 5 July 8 Sheets-Sheet 6 J. M. HOTHERSALL Filed March so, 1940 CAN MAKING MACHINE 8 Sheets-Sheet 7 ZOZ ' Qzze) gflNilfZNToRg J. M. HOTHERSALL 01m MAKING MACHINE Filed March so, 1940 July 6, 1943.-

8 Sheets-Sheet 8 INVENTOR ATT NE Patented July 6, 1943 umrs STATES New OFFICE CAN MAKING MACHINE John M. Hothersall, Brooklyn, N. Y., assignor to American Can Company, New York, N. Y., a corporation of New Jersey Application March 30, 1940, Serial No. 327,027

Claims.

The present invention relates to a cam making machine and has particular reference to an improvement in forming a plural layer fold in a can body blank from which a can is made which has a tearing strip in a folded collar section adjacent one end thereof.

An object of the invention is the provision in a can making machine of devices wherein a double bend step is formed in a can body blank in one operation and is thence folded inwardly toward the body of the blank to provide a plural layer fold therein so that an integral collar section for a can made from the blank will result.

Another object is the provision of such a machine which bends the folded step down flat against the body of the blank and forces sections of the latter out of the original plane of the blank so that what will be the exterior wall of the can made from such a blank will be straight and smooth at the collar section.

Another object is the provision of a machine of this character wherein the blanks are operated upon in progressive stages at a plurality of working stations having devices for controlling the advancement of the blanks and for holding them in proper position while being operated upon.

Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description, which,

taken in connection with the accompanying a preferred embodiment hodying the instant invention, with parts broken away;

Fig. 2 is a perspective view of a can body blank which is adapted to be operated on in the machine shown in Fig. l;

3 is a-perspective view showing one of the various stages of operation on the blank illustrated in Fig. 2;

Figs. l, 5 and 6 are enlarged fragmentary sectional and perspective views showing other stages of operation on the blank shown in Fig. 2;

Fig. 7 is an enlarged horizontal section of the apparatus taken substantially along the broken line 5-7 in Fig. 1;

8 is a longitudinal and vertical section taken substantially along the broken line 8-8 in Fig. '7, with parts broken away;

Fig. 9 is a horizontal section taken substantially along the broken. line 99 in Fig. 8;

Fig. 10 is a sectional detail taken substantially along the broken line |ill 0 in Fig. 9;

Fig. 11 is a longitudinal section taken substantially along the .broken line I I-l I in Fig. 9, with parts broken away;

Fig. 12 is a sectional detail of certain of the machine parts shown at the lower left of Fig. 11;

Fig. 13 is an enlarged longitudinal section taken substantially alon the line l3l3 in Fig. 7, with parts broken away;

Fig. 14 is a transverse section taken substantially along the line ldl4 in Fig. 13;

Fig. 15 is an elevational detail as viewed from a plane indicated by the line l5-l5 in Fig. 7, with parts broken away;

Fig. 16 is a sectional detail taken substantially along the line lE--i 6 in Fig. 8, parts being broken away;

Figs. 17 and 18 are enlarged sections taken substantially along the line l'|-l| in Fig. '7 and showing the movable parts in different positions, with parts broken away;

Figs. 19, 20, 21, 22 are transverse sections taken substantially along the respective lines |9l9, 20-29, 2I2I, 22--22 in Fig. 17, with parts broken away; and

Fig. 23 is an enlarged sectional detail of one of the suction cups illustrated in Fig. 20.

As a preferred embodiment of the invention the drawings disclose a machine for producing a folded collar section in a can body blank A (Fig. 2) from which a can is made of the character shown in my United States Patent 2,117,324, issued May 17, 1938. In such a machine the blank A is propelled along a predetermined path of travel which extends through a plurality of working stations at which various operations are performed on the blank.

At the first of these stations the blank is preferably notched as indicated at B (Fig. 3) in the region where the plural layer fold is to be subsequently formed. At the second operating station a double bond step or offset C (Fig. 4) having a connecting wall section D is formed in the blank adjacent one of its long or transverse edges. As the next operation in forming this plural layer collar the step C is folded inwardly toward the body of the blank to provide a partial fold, as shown in Fig. 5.

The folding of the collar section is completed at the next station where th partially collapsed or folded step C is bent down fiat against the body of the blank as shown in Fig. 6. This same operation preferably forces a portion of the blank adjacent the step, out of the plane of the body of the blank so that the surface which will be the outside of the can made from such a blank will be flush or straight and smooth at the collar section.

The machine shown in the drawings for performing these operations on the blank A is primarily a conventional punch press having side frames I i (Fig. 1) which carry a bed I2 on which an extended work table I3 is supported. The side frames II extend above the table and carry a crank shaft I4 and fly-wheel I5. The crank shaft is the main shaft of th machine and may be rotated by suitable power applied to the fly wheel.

The blanks A to be operated upon are preferably fed from a stack of such blanks retained in a magazine I8 (Figs. 1, '1 and 8) located adjacent the outer end of the work table I3. This magazine includes a pair of rear vertical angle iron guides I9 and a front flat vertical guide 2| which retain the blanks in the magazine.

The angle iron guides I9 are secured to longitudinal guide members 23 which are bolted to the top of the work table adjacent its outer edges. The fiat guide rail 2| is secured to a cross bar 24 the outer ends of which are bolted to the guide members. The stack of blanks within the magazine is supported on a pair of spaced rails 26 which rest on top of the work table and which are adjustably secured to brackets 21 bolted to the top of a step extension 28 of the table,

The blanks are fed from the bottom of the magazine and for this purpose the lowermost blank in the magazine is first partially withdrawn by a suction cup 3| (Figs. 7 and 8). The suction cup is located directly under the magazine I8 in an opening 32 which is formed in the work table I3. The cup is carried on the upper end of a hollow vertically movable slide 34 carried in a slidebearing 35 formed on a bracket 36 secured to the bottom of the work table. The lower end of the slide carries a flexible tube 31 which communicates with the interior of the slide and the suction cup and which leads to any suitable source of vacuum.

Vertical movement of the slide 34 in its bearing 35 is preferably effected by an actuating lever M which is mounted on a pivot shaft 42 carried in bearings 43 formed in the slide bracket 36. At its inner end the lever is formed with a segment gear 45 which meshes with a rack 46 formed on the cup slide 34. The outer end of the lever is connected by a link 41 to a cam yoke 48 (see also Figs. 9 and 10) which carries a cam roller 49 operating in a cam groove of a face cam 52.

Face cam 52 is mounted on a continuously r0 tating cross shaft 55 which is journaled in bearings 56 formed on a pair of spaced depending brackets 51 secured to the bottom of the work table I3. The cross shaft 55 is rotated by an endless chain SI engaging a sprocket 62 on the cross shaft and also engaging a sprocket 63 mounted on an auxiliary driving shaft 64. The auxiliary driving shaft is journaled in bearings 65 (see also Fig. 16) formed in the press frame I I.

The auxiliary drive shaft 64 is driven by an endless chain 61 (Fig. 1) engaging a sprocket 68 carried on the outer end of the shaft and cup engages against and clings to the lowermost blank A in the magazine I8. On the down stroke the cup draws the middle portion of the engaged blank down between the support rails 26 and against the work table I3 so that it can be engaged by feeding or advancing devices which will be now described.

While the lowermost blank in the magazine is thus bowed down against the work table I3 it is pushed out from under the stack of blanks in the magazine and advanced along the work table by a pair of spaced and parallel reciprocating feed bars 12 (Figs. '1, 8 and 14) which extend the full length of the machine. These feed bars slide in grooves 13 which are formed in the work table.

At the rear end the feed bars 12 carry a pair I of fixed feed dogs 15 which have overhanging also engaging a driving sprocket 69 which is carlips 13. It is these dogs that first engage the blank and remove it from the magazine on a forward stroke of the bars. Intermediate their lengths th bars are also provided with spring pressed feed dogs 18 which successively engage behind the blank and advance it along the work table in a step-by-step advancement with each forward stroke of the feed bars.

During this travel along the work table I3 the blanks are maintained in a straight line path of travel by the side guides 23. Provision is also made for holding the advanced blanks in position against return with the feed bars on their back stroke. For this purpose there are provided friction shoes 19 (Figs. '7, 13 and 14) urged by springs (not shown), which shoes are retained in rails BI secured to the inside surface of the side guides 23. These friction shoes bear down lightly on the blanks as they pass along their path of travel.

The feed bars 12 are reciprocated in unison by a feed arm (Figs. 1, 8 and 9) which rocks on th cross shaft 55. The upper end of the arm is connected by a short link 86 to a slide block 81 (see also Fig. 7) to which the feed bars are secured. The block slides in a slideway 88 formed in the work table I3 and is retained in place by gibs 89 secured to the bottom of the table.

Rocking movement of the feed arm 85 on the cross shaft 55 is brought about by a short actuating arm 92 (Figs. 8 and 9) which is formed integrally with the feed arm. The actuating arm is connected by a link 93 to a cam arm 94 (see also Fig. 16) which is mounted on a pivot pin 95 secured in a bearing 96 formed in the press frame H.

The cam arm 94 carries a cam roller 91 which operates in a suitable cam groove formed in a combination edge and face cam 98 mounted on the auxiliary drive shaft 64. It is the rotation of this cam that rocks the actuating arm 92 and the feed arm 85 to bring about the reciprocation of the feed bars 12 in time with the other moving parts of the machine.

A blank A advanced along the work table I3 by the feed bars 12 is first brought into an idle station and on the next stroke of the feed bars it is shifted into a notching station where the notches B hereinbefore mentioned are formed in the blank. These notches are cut in the blank by a pair of notching devices I00 (Figs. 1, 7, 8, 13, 14 and 15) which are located one on each side of the machine.

Each notching device I00 includes a vertically movable punch IOI (Figs. 7 and 13) and a cooperating stationary die I02. The die is formed in a die block I03 which is secured in a recess I04 formed in the blank guides 23. The punch IUI is carried on a vertical slide I06 disposed in slideways IB'I formed in a slide frame I08. The slide fram is bolted to the die block I03.

The punch slides I86 are moved up and down in their slideways I01 in time with the advancement of the blanks A along the work table. This is efiected by toggle links III which at one end are connected by pins II2 to the punch slides. Th opposite ends of the links are connected to arms II3 which are mounted on a cross shaft H5. The shaft extends through vertical slots IIB formed in the punch slides and is carried in bearings I I! formed in the slide frames I68.

The cross shaft II5 carries a rocker arm I2I which at its outer end is connected to a crank arm I22. The crank arm is also connected by a pivot pin I23 (Fig. to a disc I24 mounted on the constantly rotating shaft 55.

Hence as the disc I24 rotates, it shifts the crank arm I22 and thereby rocks the actuating arm I2I and the toggle arms H3 which in turn raise and lower the punch slides I85. On the up stroke of the punch slide a blank A is advanced into notching position over the notching dies I02 and on the down stroke the punches IGI cut through the blank and thus form the notches B.

After the notching operation the notched blank is advanced by the feed bars I2 into an idle station and then, on the next feeding stroke, into a step bending station which forms the double bend step C hereinbefore mentioned.

At the bending station (Figs. 1, 1'7, 18, 19 and 20) the notched blank A is received on a multipart platform which extends transversely of the machine. The platform comprises a central block I3! and a pair of outer end plates I32.

The central block I3! is located between the feed bars 72 in a rectangular opening I3 1 formed in the work table l3. The block is mounted on a plate I which is backed up by compression springs I35. There are preferably four of these springs located adjacent the corners of the plate and disposed in spring pockets I 3'! formed in a carrier member I38 secured to the bottom of the Work table I3.

The block plate I35 is also carried on the upper end of a vertical rod MI. This rod extends down through a bore I42 in the spring carrier member I38 and is secured in a vertically movable cross beam I43.

The end plates 332 of the platform are located in recesses M5 formed in the top of the work table I3 and are backed up by compression springs I 45. There are preferably four of these springs under each plate adjacent the corners thereof and they are disposed in spring pockets I ll formed in the work table. Each plate 132 is also carried on the upper end of a vertical rod I 38 which extends down through a bore I49 in the work table and at its lower end is secured in the cross beam Hi3.

Vertical movement of the platform section iSl, I32 is effected by a link lEI (Figs. 8, 9 and 11) which connects the cross beam MS with the outer end of a bell crank lever I52. The lever is mounted on a pivot pin I53 secured in a lug I54 formed on an underslung bracket E55 bolted to the press bed I2. The bell crank lever carries a cam roller I56 which operates against the outer periphery of a combined edge and face cam I5! mounted on the auxiliary drive shaft t l.

A blank A received on the platform is properly located by a permanent magnet I58 (see also Fig. 20) which is secured to the top of the central block I3I. The magnet acts as a drag on the entering blank and thereby keeps the blank edge in contact with the feed dogs I8 of the feed bars I2 and thus causes the blank to stop positively in the proper location when the feed bars reach the end of their forward stroke. The magnet thus prevents any overthrow or misalignment of the blank.

After the blank is located on the platform it is held against shifting by a pair of suction cups I59 (see also Fig. 23) There is one of these suction cups associated with each end plate I32 of the platform. The cups are located in openings I60 formed in the platform end plates and are attached by hollow screws I6I to the upper ends of vertical pipes I62. The lower ends of the pipes are secured in the cross beam I 33 and are also connected to flexible tubes IE3 which lead to a vacuum valve unit generally indicated by the numeral I64 (Figs. 11 and 12).

A valve in the vacuum valve unit Ili l opens and closes communication between the suction source and each suction cup I59 in time with the reception and discharge of the blank on the platform sections I35, I32. This holds the blank in position or releases it again for further advancement at the proper time. The valve unit includes a housing I65 (Figs. 9, 11 and 12) which is secured to a bracket I68 bolted to the press bed I2. The flexible tubes 553 are secured in this housing and communicate with a cylinder bore Ifil in which a cylindrical valve E68 has longitudinal move ment. Adjacent the ends of the tubes 553, the valve is formed with a longitudinal surface groove IE8 which is long enough to effect communication between the ends of the two tubes. The valve E58 is also formed with a transverse passageway I'll? which at one end extends into the groove I69.

The other end of the passageway l'lil termihates at the surface of the valve and is adjacent a port EH formed in the valve housing and terminating at the wall of the cylinder bore. This port communicates with a pipe I12 which is threaded into the valve heusing and which leads to a suitable source of vacuum.

In one position of valve I68 (shown in Fig. 12) the passageway Iii? is in register with the port ill and the groove I59 is in alignment with both tube I 53. Communication is thus established between the cups 59 and the source of vacuum and a blank on the platform at such time is held against shifting. In another position of the valve I68 the passageway i'iil is out of register with the port I?! and the suction on the cups is cut off. A blank on the platform at such a time thus is free to move.

Shifting of the valve I68 in the cylinder bore of its housing 55 to bring about these conditions is performed and controlled by cam action in time with the advancement of the blank along the work table. For this purpose one-end of the valve extends beyond the casing and carries a cam roller H3 (Figs. 9 and 12) which operates against an edge cam lid mounted on the auxiliary drive shaft 64. The roller is maintained in contact with the cam by a compression spring H5 (Fig. 12) Which is carried in a seat I'I6 formed in the opposite end of the valve. The spring presses against a cap I'll which is secured to the housing 165 and which covers the end Fig. 17. While thus positioned and while se'-' curely held on the platform by the suction cups, the blank is operated upon to form the double bend step C hereinbefore mentioned. The forming of the step is preferably brought about in one operation by a bending die which includes an upper bending steel I8I (Fig. 17), a pressure steel I82, and a lower anvil I83.

The anvil I83 (Figs. 1'7 and 19) is located to extend transversely of the work table I3 in a recess I85 formed therein and is held in place by screws I86 which extend through the table from its under side. The anvil is preferably formed in three continuing sections, one disposed between the two feed bars I2 and one on each side of the feed bars. The anvil is also formed with a notch I81. The feed bars I2 are also shouldered as at I88 (see: Figs. 7 and 8) and the upper surface of the bars beyond the shoulder extend to their ends at the lower level of the base of the shoulder.

The outer face of upper bending steel l8I is vertically aligned with the shoulder I81 in the anvil I83 and is secured in a recess I9I formed in a punch plate I92 disposed above the work table I3. The punch plate is bolted to a press slide I94 which has vertical movement in slideways I95 formed in the press side frames II (see Fig. 1). The slide is raised and lowered in time with the other movable parts of the machine by its connection by links I98 with cranks I9! formed in the press crank shaft I4.

The punch plate I92 is more accurately guided while moving vertically by pilot pins I98. These pins are secured in and extend up from the work table I3. Bearing lugs I99 formed in the punch plate (see Figs. '7 and 19) are perforated for sliding movement over the pilot pins.

The pressure steel I82 is carried in a transverse T-slot 20I formed in the punch plate I92 and is alongside the bending steel I8I. This pressure steel is maintained under a yieldable pressure created by a plurality of compression springs 282. These springs exert their pressure against a pair of pressure plates 283 which together with the springs are held in place by long bolts 204 which extend through the plates and are threaded in the punch plate I92. The pressure plates are supported on a plurality of vertical pins 206 disposed in bores 20! formed in the punch plate. These pins in turn rest on the pressure steel and thus transmit the pressure of the springs to the steel.

Hence on a downward stroke of the punch slide I94 and the punch plate I92 secured thereto, the pressure steel I82 projecting below the bending steel I8I, first comes into engagement with that portion of the blank A that overhangs the platform sections I3I, I32 and presses it firmly against the top of the anvil I83, as shown in Fig. 17. As the punch plate continues to descend, the springs 282 yield and the pressure plate continues its clamping action as the bending steel IBI comes into engagement with the blank on the platform. Following this platform, blank and bending steel descend in unison.

This action bends the overhanging edge of the blank over the stepped edge of the anvil I83, the while pulling the blank edge from its frictionally held slip grip between the pressure steel and the anvil. During this travel the bending steel forces the blank down into the notch I81 of the anvil (as shown in Fig. 18) and thereby produces the double bend step C. Following the bending operation the punch plate I92 and the platform sections I3I, I32 thereupon return to their original upper levels, the platform rising to its position flush with the top of the work table so that the stepped blank A will be in position for further advancement. It is at this time that vacuum cups I59 release their hold on the blank so that it may be further advanced.

During this forming of the step C in the blank A the feed bars I2 are held against return movement so that their shoulders I88 remain in transverse alignment with the step shoulder in the anvil I83. This locking of the feed bars is brought about by a vertical locking pin 2 (Figs. 7 and 8) which is slidably disposed in a bore 2I2 formed in the work table I 3. The pin rises each time the feed bars '12 complete a forward stroke and engages behind a cross bar 2I3 which connects the feed bars at that place. The feed bars remain locked against return movement until the locking pin is withdrawn. This movement of the locking pin is brought about by cam action as will now be explained.

The lower end of pin 2I I (Fig, 8) is connected by a link 2I5 to the outer end of a cam lever 2I6 (see also Figs. 9 and 11). The lever 2I6 is mounted on a cross shaft 2II which is carried in bearings 2I8 (Fig. 16) formed in the press frame II. The inner end of the lever carries a cam roller 2I9 which operates in a cam groove 22I of the combination edge and face cam I51 which is mounted on the auxiliary drive shaft 64.

After forming the step C in the blank A and while the punch plate I92 and associated parts are ascending the feed bars I2 are unlocked and thereupon make a return stroke. On their next forward stroke the stepped blank A is advanced into a folding station where the step C is further folded inwardly toward the body of the blank as hereinbefore mentioned.

At the folding station the blank is received over a multiple part platform which comprises a vertically movable central platform section 225 (Figs. 17, 18 and 21) which is disposed within an opening 226 formed in the work table I3 thus being located between the feed bars 12. This platform section is backed up by four compression springs 22! located at the corners thereof and disposed in pockets 228 formed in a carrier member 229 bolted to the bottom of the work table. The platform section 225 is connected with a pivot pin 232 secured to a yoke 233 which is bolted to a cross beam 234. A permanent magnet 235 carried on the top of the platform holds in position a blank received thereon.

On each side of the feed bars i2 the multiple part platform comprises end plate sections 231 which help to support the received blank. Each of these sections is backed up by four compression springs 238 disposed in pockets 239 formed in the top of the work table. Each plate section is connected with a vertical rod 242 and the two rods extend down through bores 243 formed in the work table. At their lower ends these rods are secured in the cross beam 234 one on each end of the beam.

Vertical movement of the platform sections 225, 231 is effected by a link 245 (see also Figs. 8 and 9) which connects the cross beam 234 with the outer end of an arm 246 of a bell crank lever 241. The bell crank lever is mounted on the cross shaft 2|! adjacent the lever 2I6. Another arm' 248 of the bell crank carries a cam roller 249 which operates on the outer periphery of the combined edge and face cam 98.

When the stepped blank A is delivered onto the platform sections 225, 231 they are in a raised position flush with the upper level of the feed bars 12, as shown in Fig. 17. When in proper position on the platform the step C of the blank is adjacent a lower stationary folding die 252 which is secured in a recess formed in the work table I3. This die is formed with an angular overhanging folding ledge 253.

Above the stationary folding die 252 thereis a rocker die member 255 which is located in a transverse clearance opening 256 formed in the punch plate I92. This die member carries a wedge shaped folding tool 251 which is adapted to cooperate with the ledge 253 of the stationary die for further bending the step C.

The rocker die 255 is formed with trunnions 26I (Fig. 8) which are carried in brackets 262 (see also Fig. '7) secured to the top of the work table I3. One of the trunnions carries a rocker arm 263 which is connected by a link 264 to a leg of a bell crank 265. The bell crank is mounted on a short shaft 266 (see also Fig. 9) carried in bearings 26! formed in the underslung bracket The bell crank carries a cam roller 269 which operates in a cam groove 2' of a face cam 212 mounted on a cam shaft 213 carried in bearings 214 formed in the underslung bracket I55. This shaft is rotated in time with the other moving parts of the machine by a gear 276 which is mounted on the shaft and which meshes with a gear 211 keyed to the auxiliary driving shaft 64. It is this mechanism that oscillates the rocker die member 255 at the proper time.

In one position of the rocker die 255, shown in Fig. 1'7, the inner or rear end of the folding tool 251 extends down into the path of travel of the blank A coming into the folding station and engages against the step C of the entering blank. The folding tool thus first serves as a stop for properly locating the blank on the platform 225. The magnet 235 holds the blank in this located position.

Thereafter the platform 225 moves down to a position where the upper surface of its magnet is fiush with the lower level of the step in the stationary die 252. During this descent of the platform the rocker die 255 oscillates inwardly (toward the right, Fig. 1'7) pressing the ledge portion of the tool 251 against the connecting wall D of the step C and wiping the connecting wall into folding engagement with the ledge 253 of the stationary die 252, finally coming into the position of Fig. 18. The blank slides slightly across the face of the holding magnet 235 during this folding operation. Fig. shows the shape of the blank at the end of this operation.

After such a folding action on the blank the rocker die member 255 and its tool 251 are reversely oscillated and disengage the newly formed blank which is now ready for further advancement. However, the platform 225 remains depressed during advancement of the blank into the next station.

In such advancement the blank is moved across a permanent stationary drag magnet 28I (Figs. 17 and 18) and is introduced into a bumping station which flattens the folded step C down tight against the body of the blank and further presses it below the plane of the blank so that it will be fiush and smooth on the upper side as shown in Fig. 6. This bumping action is effected by a lower stationary die member or anvil 283 and a cooperating upper bumping hammer 284 as the active elements and these will now be considered in detail.

The lower anvil 283 is located in a recess 286 formed in the work table I3 and the top of the anvil is flush with the top of the table. This anvil is formed with a depression 281. The hammer 284 is disposed in a recess 289 formed in the punch plate I92 and its lower surface is flush with the bottom of the plate. Adjacent the hammer a yieldable pressure bar 29I is located being confined in a slot 292. The pressure bar is backed up by compression springs 293 disposed in bores formed in the bar and in the punch plate at the top of the slot 292.

When the punch plate I92 descends toward a blank at the bumping station in the bend flat- 1 tening operation the pressure bar 29I first engages the blank and presses it firmly against the work table, as shown in Fig. 17. The punch plate continues to descend and the bumping hammer 284 engages against the partially folded step in the blank and flattens it down as the anvil 283 backs up the blank at that point. Continued squeezing action forces the folded section of the blank down into the anvil depression 287, as shown in Fig. 18, with the final folded result shown in Fig. 6.

Thi completes the folding of the collar section in the blank A. The blank is thereupon discharged from the machine to any suitable place of deposit on the next forward stroke of the feed bars I2.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, and it Will be apparent that various changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a, preferred embodiment thereof.

I claim:

1. In a machine for forming a closely contiguous plural layer fold in flat blanks, the combination of a work table for receiving and supporting said blanks and having die elements thereon, a press plate located above and movable toward said work table and having cooperating die elements thereon, means for moving said press plate in a single working stroke whereby said plate die elements cooperate with their associated table die elements to operate on a plurality of blanks on said work table to simultaneously form a step section in one of the blanks, and a closely pressed folded section in still another of the blanks interposed between said die elements, and other cooperating die elements on said work table for forming an intermediate folded step section in still another of said blanks coincidentally with said partial folding and pressing operations on said first mentioned blanks.

2. In a machine for forming a closely contiguous plural layer fold in flat blanks, the combination of a Work table for receiving and supporting said blanks, a press plate located above and vertically reciprocable toward and away from said work table, cooperating die elements carried by said work table and by said press plate for forming a step section in said blank durin reciprocation of said press plate, cooperating bending devices carried by said work table for further bending said blank step section during reciprocation of the press plate, and cooperating instrumentalities comprising a bumping hammer and a pressure bar carried by said work table and by said press plate for pressing the folded blank section flat against the supported blank portion while moving certain of the fiat folded blank sections out of the plane of the body of the blank, so that the side of the blank on which the fold is formed will be straight and smooth, and means to move the said blank from one means to the other.

3. In a machine for forming a closely juxtaposed plural layer fold in flat sheet metal blanks, the combination of a vertically reciprocable bending die mechanism, a vertically movable platform disposed adjacent said die mechanism to receive and to support a blank in position with an edge thereof extending into said die mechanism, means for actuating said die mechanism and for simultaneously depressing said platform relative thereto to cooperate therewith -to produce a step section in said fiat blank in a single operation, means operable against said step section for further folding the same inwardly toward the supported portion of the blank, and means to move the blank from the die mechanism to the folding means. I

4. In a machine for forming a closely juxtaposed plurallayer fold in a sheet metal blank having an offset step portion including an intermediate connecting wall, the combination of a folding die mechanism adapted to engage said connecting offset wall, a vertically movable platform disposed adjacent said folding die mechanism for receiving and supporting said blank in position with the offset portion thereof adjacent said die mechanism, and means for-actuating said die mechanism while simultaneously depressing said platform relative thereto for folding and collapsing said blank offset portion inwardly toward the supported portion of the blank while the blank is moved with the platform, and holding elements on said platform for retaining the blank against lateral displacement while permitting shifting of the blank: along the platform during the inward folding of said step section.

5. In a machine for forming a closely juxtaposed plural layer fold in fiat blanks, the combination of a work table for receiving and supporting blanks, step forming die means secured to said table, a supporting platform for holding a blank on said die means, means for yieldably supporting said platform, a second die means on said table, a press plate, means to support said plate for movement to and from said table, step forming die mean carried by said plate opposite said first mentioned die means, a bumping hammer carried by said plate opposite the second mentioned die means, means on said table between said die means for partially flattening the step in the blank formed at said first mentioned die means, means for feeding a said blank to said die means and to said flattening means, and drive means interconnecting said press plate, flattening means and said feed means to operate the aforesaid die and flattening means simultaneously and to actuate the feed means between the said forming operations.

JOHN M. HOTHERSALL. 

